Therapy for use in the treatment of tumors, acquired immunodeficiency syndrome and leukemias by dual immune biostimulation

ABSTRACT

A composition for human and animal use as a therapy for the treatment of tumors, acquired immunodeficiency syndrome and leukemias is described. The composition, for human and animal use as an antitumor agent, has a strain of bacteria  Lactobacillus reuteri  LRE 03 DSM 23879 which is able to strongly stimulate the production of pro-inflammatory cytokines (Th1) interferon INF-gamma, the cytokines exhibiting a marked antitumor activity, and/or a strain of bacteria  Lactobacillus salivarius  LS06 DSM 26037 which is able to strongly stimulate the production of dendritic cells, the dendritic cells also exhibiting a marked antitumor activity.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is the U.S. National Stage of International Patent Application No. PCT/IB2015/000602 filed on Apr. 30, 2015, the corrected version of which was published on Nov. 12, 2015, which, in turn, claims priority to Italian Application No. MI2014A000816 filed on May 5, 2014.

The present invention relates to a composition for human and animal use as a therapy for the treatment of tumors, acquired immunodeficiency syndrome and leukemias. The composition of the present invention, for human and animal use as antitumor agent, comprises a mixture comprising or, preferably, consisting of a strain of bacteria Lactobacillus reuteri LRE 03 DSM 23879 which is able to strongly stimulate the production of pro-inflammatory cytokines (Th1) interferon INF-gamma, said cytokines exhibit a marked antitumor activity, and/or a strain of bacteria Lactobacillus salivarius LS06 DSM 26037 which is able to strongly stimulate the production of dendritic cells, said dendritic cells also exhibit a marked antitumor activity.

As regards oncology, the current medical therapy is known to comprise chemotherapy, endocrine therapy, the treatment with immune response modifiers and the treatment with molecular-targeted drugs. The main purpose of antitumor chemotherapy is to kill, at any cell cycle phases, neoplastic cells and thus, reduce both primary tumor and metastasis masses.

It is known that antitumor chemotherapeutic treatments decrease the immune system activity and that a compromised immune system is unable to protect organisms against viral and bacterial infections.

In addition, it is known that chemotherapy (chemo) primarily affects the tumor but, unfortunately, it also causes side-effects on healthy tissues, specifically those with a fast proliferation and turnover, such as esophageal, gastric and intestinal mucosae, resulting in mucositis, nausea, vomiting, diarrhea, nutrient malabsorption and, thus, malnutrition.

Therefore, the common denominator of all chemotherapeutics is: bone marrow toxicity, which, in turn, leads to immunodepression and consequent infections, mainly caused by Gram-negative bacteria and fungi such as Candida, gastrointestinal epithelium toxicity and intestinal microflora toxicity (chemotherapeutic antibiotics).

Accordingly, it would be desirable to have a natural, effective and well-tolerated composition so that to lessen the adverse effects, typical of a chemotherapeutic treatment.

Thus, there is still a strong need for having an adjunctive therapy in order to prevent and/or reduce both symptoms and side effects of chemotherapy being used for the treatment of tumors.

Furthermore, there is still a need for having an adjunctive therapy to chemotherapy, being able to act on immune system by stimulating it (immunostimulation), in order to restore its efficacy, since chemotherapy is well known to entail a reduction of the immune system efficacy.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a plot reporting the cell proliferation index (P.I.) of PHA and LRE 03 in comparison to the baseline. The PBMC proliferative response under all the stimulation conditions resulted significantly higher than in absence of stimulation (baseline).

FIG. 2 shows a plot reporting the percentage of total dendritic cell in PHA and LRE 03 relative to the baseline.

FIG. 3 shows a plot reporting the percentage of helper T-lymphocytes in PHA and LRE 03 relative to the baseline.

FIG. 4 shows three plot reporting the amount of cytokine IL-12p70, IFN-γ and IL-4 being released in PHA, LPS and LRE 03 relative to the baseline.

FIG. 5 shows a plot reporting the increase relative to the baseline by LRE 03 strain. The bacterial strain Lactobacillus reuteri LRE 03 DSM 23879 increased by 6-fold and 47-fold the secretion of cytokine IL-12p70 and cytokine IFN-γ, respectively, relative to non-stimulation conditions.

FIG. 6 shows two plots reporting in panel A the increase of total dendritic cell (Lineage-/HLA-DR+) percentage induced by the strain LS 06 compared to the baseline and LPS and in panel B the increase relative to the baseline by LS 06. In particular, the bacterial strain L. salivarius LS 06 (DSM 26037) increased by 7-fold the percentage of total dendritic cells, relative to non-stimulation conditions (baseline) (panel B).

After a long and intensive research and development activity on a wide group of bacterial strains belonging to different species, the Applicant identified and selected specific bacterial strains, which suitably meet the above-cited needs.

It is an object of the present invention:

-   -   a strain of bacteria belonging to the species Lactobacillus         reuteri identified as Lactobacillus reuteri LRE03 with deposit         number DSM 23879, deposited on 5 Aug. 2010 by Probiotical SpA at         DSMZ—Deutsche Sammlung von Mikroorganismen und Zellkulturen         GmbH, under the Budapest Treaty, and/or     -   a strain of bacteria belonging to the species Lactobacillus         salivarius identified as Lactobacillus salivarius LS06 with         deposit number DSM 26037, deposited on 6 Jun. 2012 by         Probiotical SpA at DSMZ—Deutsche Sammlung von Mikroorganismen         und Zellkulturen GmbH, under the Budapest Treaty.

The Applicant found that the strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 shows a proven and surprising ability (see experimental part) to stimulate the production of pro-inflammatory cytokines (Th1) interferon INF-gamma. The strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 shows a surprising immunostimulatory activity towards the endogenous production of interferon gamma IFN-gamma. The strain of bacteria Lactobacillus reuteri LRE03 DSM 23879, selected by the Applicant, exhibits a surprising immunomodulatory activity, since it activates the immune system through the stimulation of pro-inflammatory cytokines (Th1) interferon INF-gamma. The endogenous cytokine stimulation/production does not cause toxicity, as opposed to the infusion administration of said cytokines, as in the case of exogenous cytokines.

By virtue of the strong stimulation of the production of pro-inflammatory cytokines (Th1) interferon INF-gamma, the strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 is able to exert an effective antitumor action, by counteracting and reducing tumor cell proliferation.

The Applicant also found that the strain of bacteria Lactobacillus salivarius LS06 DSM 26037 exhibits a proven and surprising ability (see experimental part) to stimulate the dendritic cell production. Dendritic cells assist the immune system in protecting organisms from outside attacks of dangerous microorganisms, such as viruses and bacteria.

Because of its strong stimulation of dendritic cell production, the strain of bacteria Lactobacillus salivarius LS06 DSM 26037 is able to exert an effective antitumor action, by counteracting and reducing tumor cell proliferation.

It is an object of the present invention a (i) mixture of bacteria comprising or, alternatively, consisting of: a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879, and/or a strain of bacteria Lactobacillus salivarius LS06 DSM 26037, for human or animal use as antitumor agent.

In an embodiment, said mixture (i) comprises or, alternatively, consists of:

-   -   a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879,         and/or     -   a strain of bacteria Lactobacillus salivarius LS06 DSM 26037,         for human or animal use in tumor treatment for counteracting         and/or reducing tumor cell proliferation, in acquired         immunodeficiency syndrome treatment and leukemia treatment.

In another embodiment, the (i) mixture of bacteria comprises or, alternatively, consists of:

-   -   a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 and a         strain of bacteria Lactobacillus salivarius LS06 DSM 26037, in a         weight ratio comprised from 1:5 to 5:1, preferably from 1:3 to         3:1, even more preferably from 1:2 to 2:1 or 1:1.

The (i) mixture of bacteria has a bacterial cell concentration comprised from 1×10⁸ UFC/g of mixture to 1×10¹² UFC/g of mixture, preferably from 1×10⁹ UFC/g of mixture to 1×10¹¹ UFC/g of mixture. Within the context of the present invention, all the above-cited mixtures are referred to, for the sake of brevity, as “the mixture of bacteria or the mixtures of bacteria of the present invention”.

It is another object of the present invention a pharmaceutical composition or a medical device composition, which is meant as a substance in compliance with the directive 93/42/EEC definition, hereinafter referred to, for the sake of brevity, as “the composition or compositions of the present invention”, said composition comprises or, alternatively, consists of:

(i) a mixture of bacteria of the present invention, as described above, and/or (ii) a mixture comprising or, alternatively, consisting of a gum, preferably an alginate or a derivative thereof, and/or a gel, preferably an Aloe gel or a derivative thereof, and/or (iii) a source of highly assimilable zinc, and/or (iv) one or more food grade or pharma grade excipients and/or additives and/or co-formulants, acceptable by the body, such as preferably fructooligosaccharides (FOS), green tea, sucralose and/or maltodextrins.

In an embodiment, which is an object of the present invention, the composition of the present invention comprises or, alternatively, consists of: (i) a mixture of bacteria of the present invention and (iv) one or more food grade or pharma grade excipients and/or additives and/or co-formulants, acceptable by the body, said composition being for human and animal use in antitumor chemotherapeutic treatments, acquired immunodeficiency syndrome treatments and leukemia treatments.

In another embodiment, which is an object of the present invention, the composition of the present invention comprises or, alternatively, consists of: (i) a mixture of bacteria of the present invention, (ii) a mixture comprising or, alternatively, consisting of a gel, preferably an Aloe gel or a derivative thereof and (iv) one or more food grade or pharma grade excipients and/or additives and/or co-formulants, acceptable by the body, said composition being for human and animal use in antitumor chemotherapeutic treatments, acquired immunodeficiency syndrome treatments and leukemia treatments. Said (ii) mixture comprises or, alternatively, consists of a gel, preferably an Aloe gel or a derivative thereof. The Aloe product, or a derivative thereof, is preferably Aloe arborescens; preferably in freeze-dried form. Aloe arborescens is preferably in freeze-dried form and exerts an anti-inflammatory action.

Furthermore, the Applicant found that the immune system (IS) activation by the composition of the present invention takes place through a “dual biostimulation”. The “dual biostimulation” consists of a first and a second biostimulations. The first biostimulation is obtained due to the presence, in the composition of the present invention, of very highly bioavailable zinc. This biologically available form of zinc stimulates the thymus to producing a greater amount (number) of lymphocytes. Said T-lymphocytes “overproduced” by the thymus produce non-toxic endogenous cytokines, such as interferon-gamma and dendritic cells.

The second biostimulation, combined with the first one, is promoted by the strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 and/or the strain of bacteria Lactobacillus salivarius LS06 DSM 26037 which, in turn, stimulate lymphocytes, now in a greater amount due to the previous thymus stimulation by the zinc, to producing more cytokines (specifically, INF-gamma and dendritic cells). In addition to the above, there is also a basal anti-inflammatory effect ensured by the presence of Aloe or a derivative thereof, preferably Aloe arborescens; preferably in freeze-dried form.

The very high bioavailability of zinc derives from the fact that it is in the form of zinc internalized inside a tyndallized bacterial cell of a bacterial strain belonging to the species Bifidobacterium lactis, preferably the strain selected by the Applicant is the strain of bacteria Bifidobacterium lactis Bb 1 DSM 17850 deposited at DSMZ on 23 Dec. 2005, being the object of the European Patent Application No. 08789404, herein incorporated by reference.

Basically, the Applicant found that the highly bioavailable zinc internalized into a tyndallized cell (inactivated cell) is able to activate the immune system (IS), specifically the thymus responsible for the production of T-lymphocytes, which produce non-toxic endogenous cytokines, such as interferon-gamma and dendritic cells.

In another embodiment, which is an object of the present invention, the composition of the present invention comprises or, alternatively, consists of: (i) a mixture of the present invention, (ii) a mixture comprising or, alternatively, consisting of a gel, preferably an Aloe gel or a derivative thereof, (iii) a source of highly assimilable and bioavailable zinc in the form of zinc internalized inside a tyndallized bacterial cell of a strain of bacteria belonging to the species Bifidobacterium lactis, preferably said strain is the strain of bacteria Bifidobacterium lactis Bb 1 DSM 17850 and (iv) one or more food grade or pharma grade additives and/or co-formulants and/or formulation technological ingredients, acceptable by the body, said composition being for human and animal use in antitumor chemotherapeutic treatments, acquired immunodeficiency syndrome treatments and leukemia treatments. Said (iv) source of highly assimilable and bioavailable zinc is present as organic zinc in the form of bacterial tyndallized product of the strain Bifidobacterium lactis Bb1 DSM 17850 (ProbioZinc®, deposited on 23 Dec. 2005 at DSMZ—Deutsche Sammlung von Mikroorganismen and Zellkulturen GmbH, by BioMan S.r.l. Company (Italy). The tyndallized bacterial product of the strain Bifidobacterium animalis ssp. lactis Bb1 DSM 17850 is in an amount comprised from 10 to 50 mg/g of composition, preferably 20 mg/g of composition.

All the above-cited compositions of the present invention are effectively applicable for use as adjunctive therapy to antitumor chemotherapeutic treatments, acquired immunodeficiency syndrome treatments and leukemia treatments.

Finally, the composition of the present invention comprises food grade or pharma grade excipients and/or additives and/or co-formulants, which allow the manufacture of pharmaceutical forms as powders, granules, tablets or capsules. It can also contain, for example, fructooligosaccharides FOS and/or green tea and/or sucralose and/or maltodextrins.

The composition of the present invention comprises from 1×10⁸ to 1×10¹² of viable bacterial cells UFC/g of composition, preferably from 1×10⁹ to 1×10¹¹ of viable bacterial cells UFC/g of composition. The composition of the present invention is preferably recommended to be administered 1-2 times daily for 4-12 weeks.

The composition of the present invention comprises said Aloe, advantageously freeze-dried Aloe arborescens in an amount comprised from 1 to 25% by weight, relative to the weight of the composition; preferably from 5 to 15% by weight, relative to the weight of the composition. The composition of the present invention may contain freeze-dried Aloe arborescens (Alagel™) for example 1.5 gram/dose.

In light of its overall mechanism of action, the composition of the present invention is able to make the side effects of a chemotherapeutic treatment more tolerable in individuals with a tumor disease.

In an embodiment, the composition of the present invention comprises the (i) mixture of the present invention (having a bacterial cell concentration comprised from 1×10⁸ UFC/g of mixture to 1×10¹² UFC/g of mixture, preferably from 1×10⁹ UFC/g of mixture to 1×10¹¹ UFC/g of mixture) comprising or, alternatively, consisting of:

-   -   a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879, or     -   a strain of bacteria Lactobacillus salivarius LS06 DSM 26037, or     -   a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 and a         strain of bacteria Lactobacillus salivarius LS06 DSM 26037, in a         weight ratio comprised from 1:5 to 5:1, preferably from 1:3 to         3:1, even more preferably from 1:2 to 2:1 or 1:1, and/or         fructooligosaccharides FOS and/or green tea and/or sucralose         and/or maltodextrins.

Indeed, the strain L. reuteri LRE03 DSM 23879 is able to significantly stimulate the endogenous production of interferon-gamma (IFN-γ). The ability of the strain L. reuteri LRE03 DSM 23879 to induce the release of cytokines, in particular interferon-gamma INF-gamma, by the primary cells of immune system was quantified by co-incubation thereof with PBMCs (Peripheral Blood Mononuclear Cells) isolated from peripheral blood of healthy adult individuals. The results showed a stimulation of IFN-gamma secretion with a concentration of 480 pg/ml, namely 47-fold greater than the control. The IFN-gamma production was assessed in the culture supernatant after 5 days of stimulation relative to non-stimulation conditions (baseline). Interferon-gamma (IFN-γ) has hindrance properties against viral and bacterial infections, similarly to the other interferons, and non-physiological cell proliferation, which is mediated by changes of cytoskeleton and cell membrane, modulations of oncogene product expression and regulation of the cell differentiation process (protraction of almost all the phases of mitosis both in normal and tumor cells). IFN-γ also shows a pivotal and characteristic immunomodulatory effect, by stimulating the activity of both cells specialized in the body's immune response such as macrophages, monocytes, neutrophils and unspecialized cells such as platelets, endothelial and epithelial cells, fibroblasts and parenchymal cells.

The composition of the present invention ensures a suitable amount (2 mg/dose) of highly assimilable zinc internalized by the microorganism Bifidobacterium lactis Bb1. The highly bioavailable (internalized) zinc is in the form of a tyndallized (inactivated) cell. This form of zinc is very bioavailable and, thus, more easily assimilable by the organism. The zinc ion, being bioavailable and readily assimilable by the organism, plays a pivotal role and a direct action towards the thymus, which is responsible for the stimulation/production of lymphocytes, which produce more cytokines.

The strain of bacteria Bifidobacterium lactis Bb 1 DSM 17850 was deposited at DSMZ on 23 Dec. 2005, by BioMan S.r.l. Company (Italy). Indeed, the strain of bacteria Bifidobacterium lactis Bb 1 DSM 17850 is able to accumulate zinc inside the cell during its growth in a liquid culture medium. The dietary zinc accumulated inside the cell (ProbioZinc®) has an assimilability 17-fold greater than zinc gluconate and 31.5-fold greater than zinc sulfate, as shown in an in vitro study carried out on Caco-2 cells in a Transwell system. The high assimilability of the trace element zinc allows to effectively counterbalancing deficiency conditions even at very low dosages. Furthermore, zinc is known for playing an important role on the immune system, specially the thymus, the organ where the production of T-lymphocytes takes place which, when differentiate to CD4+ T-lymphocytes (helper T-lymphocytes), secrete a series of cytokines such as IL-12 and IFN-γ. Said zinc mechanism of action is synergistic with that of the strain L. reuteri LRE03 DSM 23879.

In light of its overall mechanism of action, the composition being object of the present invention is effectively applied for use as adjunctive therapy in individuals with tumor diseases and undergoing chemotherapy, as well as in antiretroviral treatments in individuals with Acquired Immunodeficiency Syndrome (AIDS) and leukemia treatments.

Experimental Part

The Applicant tested the immunomodulatory properties of the strain of bacteria Lactobacillus reuteri LRE 03 (ID1777) DSM 23879, as described below.

Specifically, the investigation was conducted after different times of stimulation, so that to analyze both cytokines involved in innate immunity and those responsible for acquired immunity.

a) Bacterial Cultures and Growth Conditions

Firstly, bacterial cultures of the strain of bacteria Lactobacillus reuteri LRE 03 DSM 23879 were prepared under specific growth conditions. The strain was cultured in Man Rogosa Sharpe (MRS) medium, in a thermostatic bath at 37° C. As regards the immunomodulatory experiments, after a growth period of approximately 16 hours, bacteria were subcultured for 6 hours, under the above-cited conditions, in order to reach the exponential growth phase. Then, they were washed twice with sterile phosphate-buffered saline (PBS, pH 7.2); the physiological status and the number of cells were determined with a cytofluorimetric technique by using the commercial kit “Cell Viability Kit with liquid beads”, marketed by Becton Dickinson Company, following the manufacturer's instructions. The cells were thus brought to the optimal concentration established in preliminary experiments and used in subsequent tests.

b) Peripheral Blood Mononuclear Cell Separation

Next, peripheral blood mononuclear cells were separated. The peripheral blood mononuclear cells (PBMC) were separated by density gradient centrifugation. For this aim, 20 ml of “buffy coat” of healthy donors from the Immuno-transfusion Service of Ospedale di Borgomanero (Italy) were used for each experiment, thus obtaining an average yield of 200×10⁶ PBMC/buffy. The amount of separated cells was determined by cell count in Burker's chambers, using Turk's dye, which allows to discriminating between mononuclear and polymorphonuclear cells. Cells were brought to a concentration of 2×10⁶ cells/ml in RPMI-1640 growth medium (Invitrogen), supplemented with 10% heat inactivated Bovine fetal serum (FCS, Gibco), 1% glutamine and 25 mM Hepes.

c) PBMC Stimulation

Next, the peripheral blood mononuclear cells (PBMC) were stimulated with the bacterial strain. After separation, PBMCs were stimulated with the bacterial strain for 1 and 5 days. The internal controls for each experiment were as follows:

Negative control: PBMCs alone 1 day control: PBMCs stimulated with 1 μg/ml Lipopolysaccharide (LPS; Escherichia coli, serotype 055:B5, Sigma Chemicals Co., St. Louis, Mo.). 5 days control: PBMCs stimulated with 1 μg/ml Phytohaemagglutinin (PHA-P; Sigma Chemicals Co., St. Louis, Mo.).

At the different times of analysis, cultures were centrifuged at 1500 rpm for 10 minutes. Supernatants were taken and stored at −20° C. until analysis. The cells were used for subsequent tests.

d) Cell Proliferation Analysis

Then, the cell proliferation analysis was performed. Cell proliferation was assessed with a cytofluorimetric technique by using the bromodeoxyuridine (BrdU) nuclear labeling protocol. This method was developed as alternative to the more traditional radiolabeling system with tritiated thymidine. Particularly, cell cultures were added with a mixture of 5-bromo-2′-deoxyuridine (BrdU) and 2′-deoxycytidine (dC), either at 20 μM final concentration. Following to 16-hour incubation at 37° C. under humidified atmosphere, 5% CO₂, the cell proliferation was analyzed by a cytofluorimetric technique. The culture supernatants were harvested and stored at −20° C. until analysis. Following to fixation and cell wall permeabilization, the cellular DNA was labeled with anti-BrdU FITC-conjugated monoclonal antibody (mAb) (Becton Dickinson). The cells were analyzed within 24 hours from their preparation by using a cytofluorimeter FACScalibur from Becton Dikinson Company and the analysis program CellQuest.

Results were expressed as cell proliferation index (P.I.), being calculated as ratio of the percentage of proliferating cells in the presence of stimulus and the percentage of the same in the absence of stimulation. A P.I. value greater than 2 was considered acceptable (cut-off value). In all the experiments, stimulation with the mitogen (PHA) as control always resulted greater than the cut-off value, confirming that PBMCs were viable and with proliferative capability.

e) Analysis of Molecules Characterizing Individual Cell Subpopulations

Next, the analyses of molecules characterizing the individual cell subpopulations were performed. As regards the immunophenotypic characterization, the cells were incubated for 30 minutes in the dark, with different combinations of the following monoclonal antibodies (mAb) conjugated to fluorescein isothiocyanate (FITC), phycoerythrin (PE) or peridinin chlorophyll protein (PerCP): CD3, CD4, CD8, CD14, CD16, CD19, CD20, CD56, HLA-DR. After incubation, the samples were washed, fixed with a solution containing 1% paraformaldehyde and stored at 4° C. Within 24 hours from preparation, the samples were analyzed by a cytofluorimeter FACScalibur, the cells being selected so that to exclude contaminant cellular debris from analysis.

f) Cytokine Dosage

Next, the cytokine dosage was performed. Cytokine concentration in the culture supernatants was determined by E.L.I.S.A. assay (Enzyme-Linked Immunoabsorbent Assay). Specifically, for cytokine (IL-4, IL-10, IFN-γ and IL-12p70) dosage, the kits “Human ELISA Ready-SET-Go” from eBioscence Company, San Diego Calif. were used.

g) Statistical Analysis

A statistical analysis by using the paired Student's t test was performed. A p<0.05 value was considered significant.

Results

i) The proliferative response induced by the strain of bacteria Lactobacillus reuteri LRE 03 DSM 23879 was determined. In vitro analysis of cell proliferation is a very useful biological parameter for investigating the immune system functioning. In order to analyze whether the tested bacterial strain could affect the induction of lymphocyte proliferation, peripheral blood mononuclear cells (PBMC) were stimulated with the bacterial strain Lactobacillus reuteri LRE 03 DSM 23879. Phytohaemagglutinin (PHA), which is a mitogenic stimulus able to induce T-lymphocyte polyclonal proliferation, was used as positive control. PBMCs were separated from peripheral venous blood samples of 4 healthy male donors, average age of 40 years (range 21-52 years), from the Transfusion Service of Ospedale S.S. Trinità, Borgomanero (Novara).

As shown in FIG. 1, where the cell proliferation index (P.I., see the above-described methods) is reported, the PBMC proliferative response under all the stimulation conditions resulted significantly higher than in absence of stimulation (baseline).

In FIG. 1, the Mean±standard error of the mean (S.E.M.) of 4 independent experiments is shown. The statistical significance was calculated by using the Student's t test. p<0.05 values have to be considered statistically significant, as compared to the baseline (non-stimulated PBMCs).

ii) The effects of the bacterial strain Lactobacillus reuteri LRE 03 DSM 23879 on the different cell subpopulations were assessed. In order to detect which cell subpopulations were induced to proliferate following to stimulation with the tested probiotic strain, a multiparametric flow cytometry analysis was performed. The subsequent figures (FIG. 2 and FIG. 3) show the percentage of the main cell subpopulations involved both in natural and acquired immune response.

iia) Natural Immunity. After one day, the stimulation with the bacterial strain Lactobacillus reuteri LRE 03 (DSM 23879) caused a change in total dendritic cell (Lineage-/HLA-DR+) percentage.

In FIG. 2, the proliferative response Mean±S.E.M. of 4 independent experiments is shown. The statistical significance was calculated by using the Student's t test. p<0.05 values have to be considered statistically significant, as compared to the baseline (non-stimulated PBMCs).

iib) Acquired Immunity. After five days, the stimulation with the bacterial strain Lactobacillus reuteri LRE 03 DSM 23879 caused a significant increase in helper T-lymphocytes (CD3+/CD4) percentage.

In FIG. 3, the Mean±S.E.M. of 12 independent experiments is shown. The statistical significance was calculated by using the Student's t test. p<0.05 values have to be considered statistically significant, as compared to the basal condition (non-stimulated PBMCs).

iii) Cytokine secretion. The different spectrum of cytokines secreted by cell subpopulations involved in immune responses plays a pivotal role in selecting the effector system to be used in response to a specific antigenic stimulus. T-lymphocytes represent the main effector and regulatory cells of cell-mediate immunity. In response to an antigen or pathogenic agent, T-cells synthetize and secrete a variety of cytokines required for growth and differentiation and as activating factors of other immunocompetent cells. In order to investigate whether the tested bacterial strain would induce a different cytokine secretion by PBMCs, said cells were activated for 1 and 5 days. The amount of cytokines (IL-12p70, IFN-γ and IL-4) being released in the culture supernatants was measured by E.L.I.S.A. assay.

iv) Cytokines with predominantly pro-inflammatory action. The induction of cytokines IL-12p70 and IFN-γ, as main representatives of cytokines with predominantly pro-inflammatory action was assessed. As shown in FIG. 4, the bacterial strain Lactobacillus reuteri LRE 03 (DSM 23879) is able to induce a significant increase of both the tested cytokines, relative to basal conditions.

v) Cytokines with predominantly immunoregulatory action. The induction of cytokines IL-4, as main representatives of cytokines with predominantly immunoregulatory action was assessed. As shown in FIG. 4, the tested bacterial strain Lactobacillus reuteri LRE 03 (DSM 23879) shown to be able to induce a reduction of cytokine IL-4 secretion, relative to basal conditions.

In FIG. 4 the Mean±S.E.M. of 4 independent experiments is shown. The statistical significance was calculated by using the Student's t test. p<0.05 values have to be considered statistically significant, as compared to the baseline (non-stimulated PBMCs). The production of cytokines IL-12p70 was assessed in culture supernatants after 1 day of stimulation. IFN-γ and IL-4 production was assessed in culture supernatants after 5 days of stimulation.

Data relative to the dosage of cytokines secreted by PBMCs following to stimulation with the bacterial strain Lactobacillus reuteri LRE 03 DSM 23879 underlined the capability of the strain itself to significantly increase pro-inflammatory cytokines. Specifically, the bacterial strain Lactobacillus reuteri LRE 03 DSM 23879 increased by 6-fold and 47-fold the secretion of cytokine IL-12p70 and cytokine IFN-γ, respectively, relative to non-stimulation conditions (baseline, FIG. 5).

Considering the marked ability of the bacterial strain Lactobacillus reuteri LRE 03 DSM 23879 to stimulate the cytokine IFN-γ secretion, the results of the present study were compared to those obtained from experiments with other bacterial strains, all belonging to Probiotical S.p.A. collection. Specifically, the increase relative to the baseline was compared, namely the fold change of the IFN-γ amount, relative to non-stimulation conditions (baseline).

As shown in table 1, the bacterial strain Lactobacillus reuteri LRE 03 (DSM 23879) resulted the best IFN-γ inducing agent relative to both strains of the same species and strains of different species, all belonging to the genus Lactobacillus.

In Table 1, the increase of cytokine IFN-γ induced by stimulation with different lactobacilli and bifidobacteria, compared to the baseline, is shown.

Experimental Part

The Applicant tested the immunomodulatory properties of the bacterial strain Lactobacillus salivarius LS 06 DSM 26037, as described below.

Specifically, the immunomodulatory properties towards total circulating dendritic cells of the probiotic strain Lactobacillus salivarius LS 06 DSM 26037, previously characterized from both the microbiological and molecular point of views, were assessed. In particular, after 24 hours of stimulation, a multiparametric flow cytometry analysis, by selecting the DCs in peripheral blood mononuclear cells from healthy adults donors, was carried out.

a) Bacterial Cultures and Growth Conditions

The strain was cultured in Man Rogosa Sharpe (MRS) medium, in a thermostatic bath at 37° C. As regards the immunomodulatory experiments, following to a growth period of approximately 16 hours, the bacteria were subcultured for 6 hours, under the above-cited conditions, in order to reach the exponential growth phase. Thus, they were washed twice with sterile phosphate-buffered saline (PBS, pH 7.2); the physiological status and the number of cells were determined with a cytofluorimetric technique by using the commercial kit “Cell Viability Kit with liquid beads”, marketed by Becton Dickinson Company, following the manufacturer's instructions. The cells were then brought to the optimal concentration established in preliminary experiments and used in subsequent tests.

b) Peripheral Blood Mononuclear Cell Separation

Peripheral blood mononuclear cells (PBMC) were separated by density gradient centrifugation. For this aim, 20 ml of “buffy coat” of healthy donors from the Immuno-transfusion Service of Ospedale di Borgomanero were used for each experiment, thereby obtaining an average yield of 200×10⁶ PBMC/buffy. The amount of separated cells was determined by cell count in Burker's chambers, by using Turk's dye, which allows to discriminating between mononuclear cells and polymorphonuclear cells. The cells were brought to a concentration of 2×10⁶ cells/ml in RPMI-1640 growth medium (Invitrogen), supplemented with 10% heat inactivated Bovine fetal serum (FCS, Gibco), 1% glutamine and 25 mM Hepes.

c) PBMC Stimulation

After separation, PBMCs were stimulated for 24 hours with the bacterial strain. The internal controls for each experiment were as follows: Negative control: PBMCs alone; 1 day control: PBMCs stimulated with 1 μg/ml Lipopolysaccharide (LPS; Escherichia coli, serotype 055:B5, Sigma Chemicals Co., St. Louis, Mo.).

After stimulation, the cultures were centrifuged at 1500 rpm for 10 minutes. Then the supernatant was discharged and the cells used for subsequent tests.

d) Total Dendritic Cells Analysis

As regards the immunophenotypic characterization, cells were incubated for 30 minutes in the dark with different combinations of the following monoclonal antibodies (mAb) conjugated to fluorescein isothiocyanate (FITC) or peridinin chlorophyll protein (PerCP): CD3, CD14, CD16, CD19, CD20, CD56 and HLA-DR. After incubation, the samples were washed, fixed with a solution containing 1% paraformaldehyde and stored at 4° C. Within 24 hours from preparation, the samples were analyzed by a cytofluorimeter FACScalibur, the cells being selected so that to exclude contaminant cellular debris from analysis.

e) Statistical Analysis

A statistical analysis by using the paired Student's t test was performed. A p<0.05 value was considered significant.

Results: Bacterial Strain Effect on Dendritic Cells

In order to determine the effect of the tested probiotic strain to the dendritic cell modulation, a multiparametric flow cytometric analysis was carried out.

As shown in FIG. 6, panel A, after 24 hours, the stimulation with the strain LS 06 induced a significant increase of total dendritic cell (Lineage-/HLA-DR+) percentage.

Specifically, the bacterial strain L. salivarius LS 06 (DSM 26037) increased by 7-fold the percentage of total dendritic cells, relative to non-stimulation conditions (baseline, FIG. 6, panel B).

In FIG. 6, panel B, the Mean±S.E.M. of 12 independent experiments is shown. The statistical significance was calculated by using the Student's t test. p<0.05 values have to be considered statistically significant, as compared to the baseline (non-stimulated PBMCs).

In Table 2, the increase of dendritic cells induced by stimulation with different lactobacilli and bifidobacteria, relative to the baseline, is shown.

CONCLUSIONS

Data demonstrated that the bacterial strain L. salivarius LS 06 induced a significant increase of total DC percentage, relative to the standard basal conditions. In particular, the bacterium LS 06 increased by 7-fold the total DC percentage.

The intestinal colonization by bacteria capable to modulating the dendritic cells, such as the strain L. salivarius LS 06 being characterized in the present study, is a very important factor in diseases characterized by an immunological imbalance.

TABLE 1 No. of Single strains Abbreviation ID Deposit No. individuals IFN-g L. casei subsp. LPC 08 1696 DSM 21718 8 7.83 ± 0.56 paracasei L. fermentum LF 11 1639 DSM 19188 8 8.67 ± 1.05 L. paracasei LPC 00 1076 LMG P-21380 8 7.83 ± 0.56 L. paracasei LPC 00 1076 LMG P-21380 4 8.06 ± 0.95 L. plantarum LP 09 1837 DSM 25710 4 22.29 ± 4.09  L. pentosus LPS 01 1702 DSM 21980 8 19.54 ± 1.68  L. reuteri LRE 01 1775 DSM 23877 4 2.79 ± 0.61 L. reuteri LRE 03 1777 DSM 23879 4 47.02 ± 4.38  L. rhamnosus LR 05 1602 DSM 19739 10 4.16 ± 1.06 L. salivarius LS 06 1727 DSM 26037 4 4.95 ± 0.92 (L166) L. salivarius DL V8 1813 DSM 25545 4 2.74 ± 0.57 B. animalis BS 01 1195 LMG P-21384 10 6.84 ± 0.81 subsp lactis Bifidobacterium DL BL07 1820 DSM 25669 4 15.25 ± 4.01  longum Bifidobacterium DL BL08 1823 DSM 25670 4 8.95 ± 1.77 longum Bifidobacterium DL BL09 1821 DSM 25671 4 12.01 ± 2.75  longum Bifidobacterium DL BL10 1824 DSM 25672 4 11.35 ± 2.09  longum Bifidobacterium DL BL11 1825 DSM 25673 4 11.85 ± 3.78  longum Bifidobacterium BL01 1239 None 4 21.9 ± 4.67 longum Bifidobacterium BL02 1295 None 4 20.84 ± 0.89  longum Bifidobacterium BL03 1152 DSM 16603 4 24.44 ± 5.45  longum Bifidobacterium BL04 1740 DSM 23233 4 19.11 ± 5.38  longum Bifidobacterium W11 1114 None 4 26.01 ± 7.40  longum Bifidobacterium W11 wt 1161 None 4 27.42 ± 6.78  longum Bifidobacterium PCB133 1687 DSM 24691 4 29.09 ± 8.25  longum Bifidobacterium BL05 1352 DSM 23234 4 14.94 ± 2.28  longum Bifidobacterium BL06 no ID DSM 24689 4 31.90 ± 3.96  longum L. acidophilus LA02 1688 DSM 21717 8 4.91 ± 0.70 L. deldrueckii LDD01 1391 DSM 22106 8 6.46 ± 0.92 subsp. delbrueckii L. fermentum LF09 1462 DSM 18298 8 0.80 ± 0.15 L. fermentum LF10 1637 DSM 19187 8 4.25 ± 0.4  L. plantarum LP01 1171 LMG P-21021 8 1.77 ± 0.42 L. plantarum LP02  91 LMG P-21020 8 4.59 ± 0.59 L. reuteri LRE02 1774 DSM 23878 4 1.19 ± 0.12 L. reuteri LRE04 1779 DSM 23880 4 1.72 ± 0.39 L. reuteri DLLRE07 — DSM 25683 4 1.00 ± 0.07 L. reuteri DLLRE08 1841 DSM 25684 4 0.93 ± 0.06 L. reuteri DLLRE09 1842 DSM 25685 4 1.22 ± 0.29 L. rhamnosus LR06 1697 DSM 21981 10 2.64 ± 0.83 L. salivarius LS01 1797 DSM 22775 10 1.44 ± 0.13 L. salivarius LS04 — DSM 24618 L. salivarius LS03 1382 DSM 22776 10 0.72 ± 0.26 L. salivarius DLV1 1806 DSM 25138 8 1.40 ± 0.13 L. salivarius LS05 1719 DSM 26036 4 1.80 ± 0.09 (L66) L. salivarius LS02 1468 DSM 20555 8 1.32 ± 0.67 B. lactis BA05 1518 DSM 18352 8 1.24 ± 0.08 B. breve BR03 1270 DSM 16604 10 2.20 ± 0.20 B. breve BR03 1270 DSM 16604 8 6.92 ± 1.02 B. pseudolongum BPS01 1812 None 8 0.64 ± 0.33 subsp. globosum B. longum B1975 1742 DSM 24709 4 2.99 ± 0.71

TABLE 2 No. of Dendritic Single strains Abbreviation ID Deposit No. individuals cells L. fermentum LF 11 1639 DSM 19188 8 0.98 ± 0.12 L. paracasei LPC 00 1076 LMG P-21380 8 1.47 ± 0.24 L. pentosus LPS 01 1702 DSM 21980 8 1.46 ± 0.28 L. reuteri LRE 03 1777 DSM 23879 4 2.11 ± 0.59 L. rhamnosus LR 05 1602 DSM 19739 10 1.84 ± 0.29 L. salivarius LS06 1727 DSM 26037 4 7.35 ± 3.52 (L166) B. animalis BS 01 1195 LMG P-21384 10 1.32 ± 0.12 subsp. lactis L. acidophilus LA02 1688 DSM 21717 8 0.76 ± 0.16 L. deldrueckii LDD01 1391 DSM 22106 8 1.14 ± 0.19 subsp. Delbrueckii L. fermentum LF09 1462 DSM 18298 8 1.23 ± 0.12 L. fermentum LF10 1637 DSM 19187 8 1.03 ± 0.19 L. plantarum LP01 1171 LMG P-21021 8 0.86 ± 0.18 L. plantarum LP02  91 LMG P-21020 8 1.27 ± 0.18 L. salivarius LS01 1797 DSM 22775 10 3.93 ± 2.01 L. salivarius LS04 — DSM 24618 L. salivarius LS03 1382 DSM 22776 10 5.96 ± 3.53 L. salivarius LS02 1468 DSM 20555 8 3.97 ± 1.80 B. lactis BA05 1518 DSM 18352 8 1.34 ± 0.47 B. breve BR03 1270 DSM 16604 10 1.83 ± 0.29 

1. A composition comprising a mixture consisting of: a strain of bacteria belonging to the species Lactobacillus reuteri identified as Lactobacillus reuteri LRE03 with deposit number DSM 23879, deposited on 5 Aug. 2010 by Probiotical SpA at DSMZ—Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, and/or a strain of bacteria belonging to the species Lactobacillus salivarius identified as Lactobacillus salivarius LS06 with deposit number DSM 26037, deposited on 6 Jun. 2012 by Probiotical SpA at DSMZ—Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, in an amount effective for antitumor chemotherapeutic treatment, acquired immunodeficiency syndrome treatment and leukemia treatment.
 2. The composition according to claim 1, wherein said mixture has a bacterial concentration comprised from 1×10⁸ UFC/g of mixture to 1×10¹² UFC/g of mixture.
 3. The composition according to claim 1, wherein said mixture comprises: a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 and a strain of bacteria Lactobacillus salivarius LS06 DSM 26037, in a weight ratio comprised from 1:5 to 5:1.
 4. The composition according to claim 1, wherein said composition further comprises an Aloe gel or a derivative thereof.
 5. The composition according to claim 1, wherein said composition further comprises a freeze-dried Aloe arborescens in an amount comprised from 1 to 25% by weight, relative to the weight of the composition.
 6. The composition according to claim 1, wherein said composition further comprises a tyndallized bacterial product of Bifidobacterium lactis Bb 1 with deposit number DSM 17850, deposited at DSMZ on 23 Dec. 2005, by BioMan S.r.l. Company.
 7. The composition according to claim 6, wherein said tyndallized bacterial product of the strain Bifidobacterium animalis ssp. lactis Bb1 DSM 17850 is in an amount comprised from 10 to 50 mg/g of the composition.
 8. The composition according to claim 1, wherein said composition further comprises one or more food grade excipients or pharma grade excipients, and/or additives acceptable by the body, and/or co-formulants acceptable by the body.
 9. The composition according to claim 1, wherein said strain of bacteria belonging to the species Lactobacillus reuteri and strain of bacteria belonging to the species Lactobacillus salivarius are in an amount effective to treat tumors in human and animal.
 10. The composition according to claim 1, wherein said composition has a bacterial concentration from 1×10⁹ UFC/g to 1×10¹¹ UFC/g.
 11. The composition according to claim 1, wherein said composition comprises a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 and a strain of bacteria Lactobacillus salivarius LS06 DSM 26037, in a weight ratio from 1:3 to 3:1.
 12. The composition according to claim 1, wherein said composition comprises a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 and a strain of bacteria Lactobacillus salivarius LS06 DSM 26037, in a weight ratio from 1:2 to 2:1
 13. The composition according to claim 1, wherein said composition comprises a strain of bacteria Lactobacillus reuteri LRE03 DSM 23879 and a strain of bacteria Lactobacillus salivarius LS06 DSM 26037, in a weight ratio of 1:1.
 14. The composition according to claim 1, wherein said composition further comprises an Aloe arborescens gel.
 15. The composition according to claim 14, wherein the Aloe arborescens gel is freeze-dried.
 16. The composition according to claim 1, wherein said composition further comprises a freeze-dried Aloe arborescens in an amount from 5 to 15% by weight, relative to the weight of the composition.
 17. The composition according to claim 6, wherein said tyndallized bacterial product of the strain Bifidobacterium animalis ssp. lactis Bb1 DSM 17850 is in an amount of 20 mg/g of composition.
 18. The composition according to claim 1, wherein said composition further comprises fructooligosaccharides (FOS), green tea, sucralose, and/or maltodextrins.
 19. The composition according to claim 1, wherein the composition further comprises highly bioavailable zinc.
 20. The composition according to claim 19, wherein the highly bioavailable zinc is internalized inside a tyndallized bacterial cell of the strain Bifidobacterium animalis ssp. lactis Bb1 DSM
 17850. 